U.S. patent application number 14/514537 was filed with the patent office on 2015-04-30 for plasma processing apparatus and method of performing plasma process.
The applicant listed for this patent is Tokyo Electron Limited. Invention is credited to Hitoshi KATO, Shigehiro MIURA.
Application Number | 20150118415 14/514537 |
Document ID | / |
Family ID | 52995763 |
Filed Date | 2015-04-30 |
United States Patent
Application |
20150118415 |
Kind Code |
A1 |
KATO; Hitoshi ; et
al. |
April 30, 2015 |
PLASMA PROCESSING APPARATUS AND METHOD OF PERFORMING PLASMA
PROCESS
Abstract
A plasma processing apparatus for processing a substrate
includes a turntable for orbitally revolving a substrate mounting
area; a nozzle portion facing the substrate mounting area and
having gas discharge ports for generating plasma; an antenna
including a linear portion extending to cover a substrate passage
area on a downstream side relative to the nozzle portion and a
separated portion, wound around a vertical axis, and generating
induction plasma in a process area to which the gas is supplied; a
Faraday shield including a conductive plate provided between the
antenna and the process area to cut off an electric field, and
slits formed to orthogonally cross the antenna and cause a magnetic
field to pass therethrough, wherein the slits are formed on aside
lower than the linear portion and a portion of the conductive plate
without the slits is positioned on a side lower than a curved
portion.
Inventors: |
KATO; Hitoshi; (Iwate,
JP) ; MIURA; Shigehiro; (Iwate, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tokyo Electron Limited |
Tokyo |
|
JP |
|
|
Family ID: |
52995763 |
Appl. No.: |
14/514537 |
Filed: |
October 15, 2014 |
Current U.S.
Class: |
427/569 ;
118/723R |
Current CPC
Class: |
C23C 16/4584 20130101;
H01J 37/32651 20130101; H01J 37/32715 20130101; H05H 2001/4667
20130101; H01L 21/68764 20130101; C23C 16/45563 20130101; H01J
37/321 20130101; C23C 16/50 20130101; H01J 37/3211 20130101; H01J
37/32669 20130101; H01L 21/68771 20130101; H05H 1/46 20130101 |
Class at
Publication: |
427/569 ;
118/723.R |
International
Class: |
C23C 16/50 20060101
C23C016/50; C23C 16/455 20060101 C23C016/455; C23C 16/448 20060101
C23C016/448; C23C 16/458 20060101 C23C016/458 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 25, 2013 |
JP |
2013-222202 |
Claims
1. A plasma processing apparatus performing a plasma process for a
substrate inside a vacuum chamber, the plasma processing apparatus
comprising: a turntable for orbitally revolving a substrate
mounting area, on which a substrate is mounted; a nozzle portion
that faces the substrate mounting area and has gas discharge ports
for discharging a gas for generating plasma linearly arranged from
a side of an outer periphery to a side of a center portion; an
antenna that includes a linear portion extending so as to cover a
substrate passage area on a downstream side in a rotational
direction of the turntable relative to the nozzle portion and a
separated portion positioned separated from the linear portion in a
plan view of the antenna, the antenna unit being wound around an
axis vertically extending in up and down directions, and generates
induction plasma in a process area to which the gas is supplied; a
Faraday shield including a conductive plate provided between the
antenna and the process area so as to be hermetically separated
from the process area and to cut off an electric field of an
electromagnetic field, and a group of slits formed so as to
orthogonally cross the antenna and cause a magnetic field of the
electromagnetic field to pass through the slits, wherein the group
of slits is formed on at least a side lower than the linear
portion, and a portion of the conductive plate without the group of
slits is positioned on a side lower than a curved portion, at which
the antenna curves from an end of the linear portion.
2. The plasma processing apparatus according to claim 1, wherein a
portion of the Faraday shield corresponding to the separated area
of the antenna is arranged on a downstream side in the rotational
direction of the turntable relative to the linear portion of the
antenna.
3. The plasma processing apparatus according to claim 1, wherein
the antenna includes another linear portion positioned on a side
opposite to the linear portion relative to the nozzle portion, and
the group of the slits is arranged on the side lower than the
another linear portion.
4. The plasma processing apparatus according to claim 1, wherein
the antenna is wound around the axis by a plurality of turns,
wherein the linear portion positioned close to the nozzle portion
is laminated by a plurality of stages.
5. The plasma processing apparatus according to claim 1, wherein
the antenna is wound around the axis by a plurality of turns,
wherein the portion of the Faraday shield corresponding to the
separated area of the antenna is arranged on a downstream side of
the rotational direction of the turntable relative to the linear
portion, and one turn and another turns of the plurality of turns
of the antenna are arranged so as to shift each other along the
rotational direction of the turntable.
6. The plasma processing apparatus according to claim 1, further
comprising: a wall portion that separates the process area in a
shape of sector having side portions along two lines radially
extending from a center of the turntable and separated in a
peripheral direction of the turntable and downward extends from a
ceiling plate of the vacuum chamber, wherein the nozzle portion
extends along the wall portion in the vicinity of the wall portion
positioned on an upstream side of the process area.
7. The plasma processing apparatus according to claim 6, wherein
the wall portion is arranged so that VI/VO equals to LI/LO where VI
designates a speed of an end of the substrate on a side of a
rotational center on the turntable, VO designates a speed of an end
of the substrate on a side of a periphery on the turntable, and LI
and LO respectively designate lengths of the process area through
which the end of the substrate on the side of the rotational center
and the end of the substrate on the side of the periphery.
8. A method of performing a plasma process plasma for a substrate
positioned inside a vacuum chamber, the plasma method comprising:
orbitally revolving a substrate by rotating a turntable after the
substrate is mounted on a mounting area provided on the turntable;
supplying a gas for generating plasma from a nozzle portion that
faces the turntable and linearly extends from a side of an outer
periphery to a side of a center portion into a process area
provided inside the vacuum chamber; generating induction plasma in
the process area by an antenna that includes a linear portion
extending so as to cover a substrate passage area on a downstream
side in a rotational direction of the turntable relative to the
nozzle portion and a separated portion positioned separated from
the linear portion in a plan view of the antenna, is wound around
an axis vertically extending in up and down directions, and
generates induction plasma in the process area to which the gas is
supplied; cutting off an electric field of an electromagnetic field
that is generated by the antenna using a conductive plate provided
between the antenna and the process area so as to hermetically
separated from the process area; and causing a magnetic field of
the electromagnetic field to pass through a group of slits formed
so as to orthogonally cross the antenna, wherein the group of slits
is formed on at least a side lower than the linear portion and a
portion of the conductive plate without the group of slits is
positioned on a side lower than a curved portion, at which the
antenna curves from an end of the linear portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is based upon and claims the benefit
of priority of Japanese Patent Application No. 2013-222202 filed on
Oct. 25, 2013, the entire contents of which are incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a plasma processing
apparatus and a method of performing plasma process.
[0004] 2. Description of the Related Art
[0005] Japanese Laid-open Patent Publication No. 2011-151343
discloses a semibatch type apparatus for providing a plasma process
to a substrate (hereinafter, referred to as a "wafer") such as a
semiconductor wafer. Specifically, Japanese Laid-open Patent
Publication No. 2011-151343 discloses that five wafers are arranged
in a peripheral direction of the turntable on the turntable and a
plasma generating portion such as a pair of opposing electrodes or
an antenna is arranged so as to face an orbit of the wafer moved
(orbitally revolved) by the turntable. According to Japanese
Laid-open Patent Publication No. 2011-151343, multiple plasma
generating portions are arranged, and a degree of the plasma
process on a surface of the wafer is adjusted by mutually changing
the lengths of the multiple plasma generating portions.
[0006] Japanese Laid-open Patent Publication No. 2013-45903
discloses a technique by which an antenna is arranged at a position
hermetically separated from an ambient atmosphere inside the vacuum
chamber and a Faraday shield having slits formed therein is
provided between the antenna and the wafer. Electric field
components of an electromagnetic field generated by the antenna are
cut off, and magnetic field components generate plasma.
[0007] However, these Japanese Laid-open Patent Publication No.
2011-151343 and Japanese Laid-open Patent Publication No.
2013-45903 do not study a technique of uniformizing a distribution
of the plasma generated on the lower side of arbitrary one of
multiple antennas.
SUMMARY OF THE INVENTION
[0008] The present invention is provided in consideration of the
above situation, and the object of the present invention is to
provide a plasma processing apparatus that can perform a process of
achieving a high uniformity on a surface of a substrate in
providing a plasma process to the substrate and a method of
performing the plasma process.
[0009] According to an aspect of the invention, there is provided a
plasma processing apparatus performing a plasma process for a
substrate inside a vacuum chamber including a turntable for
orbitally revolving a substrate mounting area, on which a substrate
is mounted; a nozzle portion that faces the substrate mounting area
and has gas discharge ports for discharging a gas for generating
plasma linearly arranged from a side of an outer periphery to a
side of a center portion; an antenna that includes a linear portion
extending so as to cover a substrate passage area on a downstream
side in a rotational direction of the turntable relative to the
nozzle portion and a separated portion positioned separated from
the linear portion in a plan view of the antenna, is wound around
an axis vertically extending in up and down directions, and
generates induction plasma in a process area to which the gas is
supplied; a Faraday shield including a conductive plate provided
between the antenna and the process area so as to hermetically
separated from the process area and to cut off an electric field of
an electromagnetic field, and a group of slits formed so as to
orthogonally cross the antenna and cause a magnetic field of the
electromagnetic field to pass through the slits, wherein the group
of slits is formed on at least a side lower than the linear portion
and a portion of the conductive plate without the group of slits is
positioned on aside lower than a curved portion, at which the
antenna curves from an end of the linear portion.
[0010] Additional objects and advantages of the embodiments are set
forth in part in the description which follows, and in part will
become obvious from the description, or may be learned by practice
of the invention. The objects and advantages of the invention will
be realized and attained by means of the elements and combinations
particularly pointed out in the appended claims. It is to be
understood that both the foregoing general description and the
following detailed description are exemplary and explanatory and
are not restrictive of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a longitudinal cross-sectional view of an
exemplary plasma processing apparatus according to an embodiment of
the present invention;
[0012] FIG. 2 is a cross-sectional plan view of the plasma
processing apparatus;
[0013] FIG. 3 is a cross-sectional plan view of the plasma
processing apparatus;
[0014] FIG. 4 is a longitudinal cross-sectional view of the plasma
processing apparatus;
[0015] FIG. 5 is an exploded perspective view of the plasma
processing apparatus;
[0016] FIG. 6 is a plan view of the antenna;
[0017] FIG. 7 is a plan view illustrating a positional relationship
between the antenna and the wafer;
[0018] FIG. 8 is a perspective view of a casing, in which the
antenna is accommodated, viewed from a lower side;
[0019] FIG. 9 is a plan view schematically illustrating a locus of
plasma covering a wafer;
[0020] FIG. 10 is a longitudinal cross-sectional view of the casing
inside which the plasma is retained;
[0021] FIG. 11 is a view schematically illustrating a state where
the plasma and a plasma generating gas changes along a passage of
time;
[0022] FIG. 12 is a longitudinal cross-sectional view of another
exemplary plasma processing apparatus; and
[0023] FIG. 13 is a characteristic diagram illustrating results of
simulation obtained by an embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0024] A description is given below, with reference to the FIG. 1
through FIG. 13 of embodiments of the present invention.
[0025] In the embodiments described below, the reference symbols
typically designate as follows: [0026] W: wafer; [0027] 1: vacuum
chamber; [0028] 2: turntable; [0029] P1: adsorption area; [0030]
P2: reaction area; [0031] 31, 32, 34: gas nozzle; [0032] 83:
antenna; [0033] 95: Faraday shield; and [0034] 97: slit.
[0035] Referring to 1 to 8, an exemplary plasma processing
apparatus of an embodiment is described. As illustrated in FIGS. 1
to 3, the plasma processing apparatus includes a vacuum chamber 1
whose plan view is substantially circular and a turntable 2 having
a rotational center at a center of the vacuum chamber 1, and is
structured to perform a film deposition process provided to the
wafer W using plasma. In this apparatus, portions of the plasma
processing apparatus are structured as described below so that a
process achieving high uniformity through the surface of the wafer
W can be performed by generating the plasma.
[0036] The vacuum chamber 11 includes a ceiling plate 11 and a
chamber body 12. In the vacuum chamber 11, a nitrogen (N.sub.2) gas
is supplied as a separation gas through a separation gas supplying
pipe 51 that is connected at a center portion on the upper side of
the ceiling plate 11. As illustrated in FIG. 1, a heater unit 7 as
a heating mechanism is provided on the lower side of the turntable
2. The heater unit 7 heats the wafers W through the turntable 2 so
that the wafers W are heated to be, for example, 300.degree..
Referring to FIG. 1, a reference symbol 13 designates an
.largecircle. ring. Further, referring to FIG. 1, a reference
symbol 71a designates a cover member of the heater unit 7, a
reference symbol 7a designates a lid for covering the heater unit
7, and reference symbols 72 and 73 designate purge gas supplying
pipes.
[0037] A core portion 21 having a substantially cylindrical shape
is attached to a center portion of the turntable 2, and a
rotational shaft 22 is connected onto the lower surface of the core
portion 21. The turntable 2 can be freely rotatable around a
vertical axis by the rotational shaft 22 in, for example, a
clockwise direction. Referring to FIGS. 2 and 3, multiple circular
concave portions 24 are provided on the surface of the turntable 2
as substrate mounting areas to receive and hold the wafers W by
dropping the wafers thereinto. The multiple concave portions 24 are
located at, for example, five positions along a rotational
direction (a peripheral direction) of the turntable 2. Referring to
FIG. 1, a reference symbol 23 designates a driving mechanism (a
rotation mechanism), and a reference symbol 20 designates a case
body.
[0038] At a position of a passage area of the concave portions 24,
four nozzles 31, 32, 41, and 42 made of, for example, quartz are
radially arranged while mutually interposing intervals in the
peripheral direction of the vacuum chamber 1. For example, these
nozzles 31, 32, 41, and 42 are attached to the vacuum chamber 1 so
as to horizontally extend from an outer peripheral wall toward the
center area C while facing the wafers W. In this example, a plasma
generating gas nozzle 32, a separation gas nozzle 41, a process gas
nozzle 31, and a separation gas nozzle 42 are arranged in this
order in a clockwise direction from the transfer opening 15
(described later). The gas nozzle 31 and the plasma generating gas
nozzle 32 respectively form a process gas supplying portion and a
nozzle portion. The separation gas nozzles 41 and 42 function as a
separation gas supplying portion. FIG. 2 illustrates a state where
an antenna 83 and a casing 90 are removed so that the plasma
generating gas 32 can be observed. FIG. 3 illustrates a state where
the antenna 83 and the casing are attached.
[0039] The nozzles 31, 32, 41, and 42 are connected to
corresponding gas supplying sources (not illustrated) through flow
rate adjusting valves. Said differently, the process gas nozzle 31
is connected to a gas supplying source for supplying a process gas
containing silicon (Si) such as a dichlorosilane (DSC) gas. The
plasma generating gas nozzle 32 is connected to a gas supplying
source for supplying the plasma generating gas such as an ammonia
(NH3) gas. The separation gas nozzles 41 and 42 are connected to
corresponding gas supplying sources for supplying the separation
gas, namely a nitrogen gas. Gas discharging ports 33 are formed on
the lower surface sides of the gas nozzles 31, 32, 34, 41, and 42.
The gas discharging ports 33 are arranged at, for example, an equal
interval and at multiple locations along a radius direction of the
turntable 2. The gas discharge ports 33 of the gas nozzles 31, 41,
and 42 are formed on lower surfaces of the gas nozzles 31, 41, and
42. The gas discharge ports 33 of the plasma gas nozzle 32 are
formed on a side surface of the plasma gas nozzle 32 on an upstream
side in the rotational direction of the turntable 2. Reference
symbol 31a in FIGS. 2 and 3 designates a nozzle cover covering an
upper side of the process gas nozzle 31.
[0040] An area lower than the process gas nozzle 31 is an
adsorption area P1 for causing a component of the process gas to be
adhered to the wafer W. Further, an area on a lower side of the
plasma generating gas nozzle 32 (an area lower than the casing 90,
described below) is a reaction area (a process area) P2 for causing
the component of the process gas adsorbing onto the wafer to react
with plasma of the plasma generating gas. The separation gas
nozzles 41 and 42 are provided to form a separation area D for
separating the areas P1 and P2. Referring to FIG. 2 and FIG. 3, the
ceiling plate 11 of the vacuum chamber 1 has a convex portion 4
substantially in a sector-like shape. The separation gas nozzles 41
and 42 are accommodated in the convex portion 4.
[0041] Next, a structure of generating induction plasma from the
plasma generating gas is described in detail. Referring to FIGS. 3
and 4, the antenna 83 formed by winding a metallic wire in a
coil-like shape is arranged on a side upper than the plasma
generating gas nozzle 32. Referring to FIG. 7, this antenna 83 is
arranged so as to bridge the passage area of the wafer W from a
side of a center portion of the turntable through a side of an
outer circumferential portion of the turntable in a plan view.
Further, the antenna 83 is wound by multiple turns, in this example
three turns, around an axis (a vertical axis) extending vertically
from the surface of the turntable 2. Said differently, in the
antenna 83, circumferential portions of the antenna 83 are
vertically laminated in three stages (three turns), and ends of
each circumferential portion are connected in series. The three
stages of the antenna 83 are connected through a matching box 84
with a high frequency power source 85 so as to be commonly
connected with the high frequency power source 85. In this example,
the frequency and the output power of the high frequency power
source 85 are, for example, 13.56 MHz and 5000 W, respectively.
[0042] Referring to FIGS. 5 and 7, the lower stage of the three
stages of the circumferential portions of the antenna 83 is formed
so as to surround a substantially oblong (rectangular) area
extending along a radius direction of the turntable 2. Therefore,
in the lower stage of the circumferential portion, portions on the
upstream and downstream sides in the rotational direction of the
turntable 2 and portions on the center side and the peripheral side
of the turntable 2 are formed to be linear. Specifically, the
portions on the upstream and downstream sides in the rotational
direction of the turntable 2 are formed along the radius direction
of the turntable, said differently, along the length direction of
the plasma generating gas nozzle 32. Further, portions on the
center side and the outer peripheral side of the lower stage of the
circumferential portion are formed to go along a tangential
direction of the turntable 2.
[0043] Here, a portion of the lower stage of the circumferential
portion formed along the length direction of the plasma generating
gas nozzle 32 on the upstream side of the rotational direction of
the turntable are called a linear portion 83a, and a portion of the
lower stage of the circumferential portion formed to be linear at a
position opposite to the linear portion 83a is called an opposite
portion 83b. A residual portion of the lower stage of the
circumferential portion extending from ends and other ends of the
linear portion 83a and the opposite portion 83b is called a curved
portion 83c. The linear portion 83a of the lower stage of the
circumferential portion is arranged at a position slightly
separated on the downstream side of the turntable 2 relative to the
plasma generating gas nozzle 32 in a plan view.
[0044] In the antenna 83, the middle stage of the circumferential
portion is laminated above the lower stage of the circumferential
portion. The middle stage of the circumferential portion is formed
to be substantially the same shape as the lower stage of the
circumferential portion and includes a linear portion 83a, an
opposite portion 83b, and a curved portion 83c. The linear portion
83a of the middle stage of the circumferential portion is laminated
on a side of the upper layer of the linear portion 83a of the lower
stage of the circumferential portion. On the other hand, the
opposite portion 83b of the middle stage of the circumferential
portion is arranged at a position apart from the opposite portion
83b of the lower stage of the circumferential portion on a
downstream side in the rotational direction of the turntable 2. In
the middle stage of the circumferential portion, the opposite
portion 83b is linearly arranged at a position close to the wafer W
(a position where an insulating member 94 described later touches)
on the turntable 2 so as to go along the length direction of the
plasma generating gas nozzle 32.
[0045] In the antenna 83, the upper stage of the circumferential
portion is laminated above the middle stage of the circumferential
portion. The upper stage of the circumferential portion includes a
linear portion 83a, an opposite portion 83b, and a curved portion
83c. The linear portion 83a of the circumferential portion is
laminated on the linear portions 83a on the side of the lower
stage. The opposite portion 83b of the upper stage of the
circumferential portion is arranged apart from the opposite portion
83b of the middle stage of the circumferential portion on the
downstream side of the rotational direction of the turntable 2 and
is arranged along the length direction of the plasma generating gas
nozzle 32 so as to be linear at a position close to the wafer W on
the turntable 2. Referring to FIGS. 6 and 7, the antenna is
indicated by a broken line. Referring to FIG. 7, the wafer W is
indicated by a solid line.
[0046] Referring to FIG. 4, at a position adjacent to the
downstream side in the rotational direction of the turntable 2
relative to the plasma generating gas nozzle 32, three stages of
the linear portions 83a are vertically laminated. At a position
apart from the above position adjacent to the downstream side, the
three opposite portions 83b are arranged side by side. As described
below, plasma of the ammonia gas (the plasma generating gas) is
quickly generated at the position in the vicinity of the plasma
generating gas nozzle 32. At the position apart from the position
in the vicinity of the plasma generating gas nozzle 32, the
inactivated ammonia gas is changed to plasma again.
[0047] The antenna 83 is arranged so as to be hermetically
separated from the inner area of the vacuum chamber 1. Said
differently, the ceiling plate 11 has an opening substantially in a
sector-like shape in its plan view on the upper side of the second
process gas nozzle 32 and is hermetically sealed by the casing 90
made of, for example, quartz. As illustrated in FIGS. 5 and 8, the
upper peripheral edge portion of the casing 90 horizontally extends
like a flange in the peripheral direction of the casing 90.
Further, the central portion of the casing 90 is recessed toward
the inner area of the vacuum chamber 1. The antenna 83 is
accommodated inside the casing 90. The casing 90 is fixed to the
ceiling plate 11 by a fixing member 91. The fixing member 91 is
omitted from illustration except for FIGS. 1 and 2.
[0048] The lower surface of the casing 90 has a wall portion 92 for
preventing a nitrogen gas or the like from intruding into the lower
area of the casing 90. Referring to FIGS. 1 and 8, the outer edge
portion vertically protrudes onto the lower side (a side of the
turntable 2) along its periphery to form the wall portion 92.
Referring to FIGS. 5 and 8, the upstream and downstream sides of
the wall portion 92 in the rotational direction of the turntable 2
extend radially from the center of the turntable 2 and are
separated so as to be apart each other in the peripheral direction
of the turntable 2. Referring to FIG. 4, the wall portion 92 is
positioned on an outside of an outer periphery of the turntable 2
on outer peripheral side of the turntable 2. When the area
surrounded by an inner peripheral surface of the wall portion 92, a
lower surface of the casing, and an upper surface of the turntable
is called a "reaction area P2", the reaction area P2 is separated
by the wall portion 92 so as to be shaped like a sector. The
above-described plasma generating gas nozzle 32 is arranged in the
vicinity of the wall portion 92 at an end on the upstream side in
the rotational direction of the turntable 2 inside the reaction
area P2.
[0049] Said differently, referring to FIG. 8, a lower end of the
wall portion 92 is formed as follows. A portion, into which the
plasma generating gas nozzle 32 is inserted, upward curves along an
outer peripheral surface of the plasma generating gas nozzle 32.
Portions of the lower end of the wall portion 92 other than the
above portion are arranged so as to have a height close to the
turntable along the peripheral direction. Referring to FIG. 4, the
gas discharge ports 33 of the plasma generating gas nozzle 32 are
formed to horizontally face the upstream side of the wall portion
92 that surround the reaction area P2 in the rotational direction
of the turntable 2.
[0050] As described above, the wafer W orbitally revolves around by
the turntable 2 and passes the areas P1 and P2 on a side lower than
the nozzles 31 and 32. Therefore, on the turntable 2, the speed
(the angular speed) of the end on the rotational center side of the
wafer W passing through the areas P1 and P2 is different from the
speed (the angular speed) of the end on the outer peripheral side
of the wafer W passing through the areas P1 and P2 differ.
Specifically, in a case where the diameter of the wafer W is 300 mm
(12 inch size), the speed of the end on the rotational center side
is one third of the speed of the end on the outer periphery
side.
[0051] Said differently, provided that the distance between the
rotational center of the turntable 2 and the end of the wafer on
the rotational center side is s, the dimension DI of the
circumference through which the end of the wafer W on the
rotational center side passes is (2.times..pi..times.s). Meanwhile,
the dimension DO of the circumference through which the end of the
wafer W on the outer peripheral side passes is
(2.times..pi..times.(s+300)). By the rotation of the turntable 2,
the wafer W moves through the dimensions DI and DO within the same
time. Therefore, provided that the speeds of the end on the
rotational center side and on the outer peripheral side of the
wafer W on the turntable are VI and VO, respectively, a ratio R
(VI/VO) of the speeds VI and VO is (s/(s+300)). In a case where the
distance s is 150 mm, the ratio R becomes 1/3.
[0052] Therefore, in a case where plasma which does not have very
high reactivity with a component of the DSC gas adsorbing on the
wafer W such as the plasma of the ammonia gas, a thin film (the
reaction product) on the outer peripheral side becomes thinner than
on the center side if the ammonia gas is changed to the plasma in
the vicinity of the plasma generating gas nozzle 32.
[0053] According to the present invention, the shape of the wall
portion 92 is adjusted to perform a uniform plasma process for the
wafer W. Specifically, as illustrated in FIG. 7, provided that the
length of a locus through which the end on the rotational center
side of the wafer W on the turntable 2 passes in the reaction area
P2 is indicated by LI, and the length of a locus through which the
end on the outer peripheral side of the wafer W on the turntable 2
passes in the reaction area P2 is indicated by LO, a ratio (LI/LO)
of LI relative to LO is 1/3. The shape of the wall portion (the
dimension of the reaction area P2) is set in response to a speed at
which the wafer W on the turntable 2 passes through the reaction
area P2. As described later, because the plasma of the ammonia gas
fills the reaction area P2, the entire surface of the wafer W is
evenly provided with the plasma process.
[0054] Referring to FIGS. 4, 5, and 6, a Faraday shield 95 is
arranged between the casing 90 and the antenna 83. The Faraday
shield 95 prevents an electric field component of an
electromagnetic field generated by the antenna from downward
directing and causes a magnetic field component of the
electromagnetic field to downward pass through. The Faraday shield
95 is formed to be substantially a box and has an opening on an
upper side. The Faraday shield 95 is made of a metallic plate (a
conductive plate) which is a conductive plate-like body and is
grounded in order to cut off the electric field. The slits 97
forming rectangular openings in the metallic plate are provided in
a bottom surface of the Faraday shield 95 to cause the magnetic
field to pass through the Faraday shield 95.
[0055] Each slit 97 does not communicate with other slits 97
adjacent to the slit 97. Said differently, a metallic plate forming
the Faraday shield 95 is positioned along the peripheral direction
and around the slits 97. The slits 97 are formed in a direction
perpendicular to the direction of the antenna 83 and are arranged
at multiple positions at an even interval along the length
direction of the antenna 83 and below the antenna 83. The slits 97
are not formed at a position corresponding to the upper side of the
plasma generating gas nozzle 32. Therefore, the ammonia gas is
prevented from changing to the plasma inside the plasma generating
gas nozzle 32.
[0056] Referring to FIGS. 5 and 6, the slits 97 are formed at
positions lower than the portions of the antenna 83 (the linear
portion 83a and the opposite portion 83b) extending linearly from
the center to the outer periphery of the turntable 2. Meanwhile,
the slits 97 are not formed on a side lower than the above
portions. Specifically, the slits 97 are not formed in an area
corresponding to the portions of the antenna 83 provided between
the linear portion 83a and the opposite portion 83b and extending
substantially in a tangential direction of the turntable 2 and an
area corresponding to a curved portion of the antenna 83 provided
between ends of the linear portion 83a and the opposite portion
83b.
[0057] Said differently, when the slits 97 are formed thoroughly
along the antenna 83, the slits 97 should be arranged at different
angles at curved portions of the antenna 83. However, in this case,
adjacent slits 97 corresponding to the curved portion of the
antenna 83 may be connected each other. Then, an effect of cutting
off the electric field becomes small. If the widths of the slits 97
are reduced to prevent the adjacent slits 97 from connecting, the
amount of the magnetic field component such as the strength of the
magnetic field in the curved portion reaching the wafer W becomes
weaker than that in the linear portion 83a and the opposite portion
83b. Further, if the distance between the adjacent slits 97 on the
area corresponding to the outside of the antenna 83 is made longer,
not only the magnetic field but also the electric field reaches the
wafer W to thereby possibly give a charging damage to the wafer
W.
[0058] Within the embodiment, in order to set the amount of the
magnetic field component such as the strength of the magnetic field
reaching the wafer W from the antenna 83 through the slits 97 to be
identical, the linear portion 83a is arranged to cover a position
where the wafer W passes and the slits 97 are formed on a side
lower that the linear portion 83a. On the side lower than the
curved portion extending from the ends of the linear portion 83a,
the slits 97 are not formed and the conductive plate forming the
Faraday shield 95 is arranged to cut off not only the electric
field component but also the magnetic field component. Therefore,
as described later, the amount of the plasma generated along the
radius direction of the turntable 2 is uniformized.
[0059] Therefore, when the slits 97 are viewed at an arbitrary
position, opening widths of the slits 97 are set to be identical in
the longitudinal directions of the slits 97. The opening widths of
all the slits 97 in the Faraday shield 95 are adjusted to be the
same. Said differently, the slits 97 are structured to set
groove-like longitudinal openings at multiple positions so that the
groove-like longitudinal openings are arranged in parallel and
perpendicular to the linear portion 83a and the opposite portion
83b of the antenna 83 between a position apart on the upstream side
in the rotational direction of the turntable 2 from the linear
portion 83a to a position apart on the downstream side in the
rotational direction of the turntable 2 from the opposite portion
83b. Between the linear portion 83a and the opposite portion 83b,
multiple reinforcing ribs (band-like conductors) are provided
between the openings (the slits 97) and arranged along the linear
portion 83a or the opposite portion 83b.
[0060] An insulating member 94 (see FIG. 4) made of, for example,
quartz is interposed between the Faraday shield 95 and the antenna
83 in order to insulate the Faraday shield 95 from the antenna 83.
The insulating member 94 is substantially shaped like a box and has
an opening on the side of the upper surface of the insulating
member 94. Referring to FIG. 7, the Faraday shield 95 is omitted
from illustration in order to explain a positional relationship
between the antenna 83 and the wafer W. Except for FIG. 4, the
insulating member 94 is omitted from illustration.
[0061] A side ring 100 in an annular shape is arranged at a
position slightly lower than the turntable 2 on the outer
peripheral side of the turntable 2. Evacuation ports 61 and 62 are
formed at two positions on the upper surface of the side ring 100
so as to be mutually separated in the peripheral direction of the
side ring 100. These two evacuation ports 61, 62 include a first
evacuation port 61 and a second evacuation port 62. The first
evacuation port 61 is positioned on a side closer to the separation
area D that is positioned on the downstream side of the turntable 2
relative to the first processing gas nozzle 31 in the rotational
direction of the turntable 2 between the first processing gas
nozzle 31 and the separation area D. The second evacuation port 62
is positioned on a side closer to the separation area D between the
plasma generating gas nozzle 32 and the separation area D
positioned on the downstream side of the plasma generating gas
nozzle 32 in the rotational direction of the turntable 2.
Therefore, the second evacuation port 62 is positioned in the
vicinity of an apex of a triangle formed by connecting a point of
the rotational center of the turntable 2, a point where the edge of
wall portion 92 on the side of the reaction area P2 intersect the
outer peripheral edge of the turntable 2, and this apex.
[0062] The first evacuation port 61 is provided to evacuate the
process gas and the separation gas. The second evacuation port 62
is provided to evacuate the plasma generating gas and the
separation gas. The upper surface of the side ring 100 has a gas
flow path 101 in a groove-like shape on the outer edge side of the
casing 90. The gas flow path 101 is provided to flow the gas into
the second evacuation port 62 and to prevent the gas from flowing
into the casing 90. The first and second evacuation ports 61 and 62
may be connected to an evacuating mechanism such as a vacuum pump
64 through evacuation pipes 63 provided with a pressure controller
65 such as a butterfly valve.
[0063] Referring to FIG. 1, a protruding portion 5 is provided at a
center portion on the lower surface of the ceiling plate 1 and
protrudes on a side lower than the ceiling plate. The protruding
portion 5 prevents the process gas from being mixed with the plasma
generating gas in the center area C. Said differently, the
protruding portion 5 includes a wall portion vertically extending
from the side of the turntable 2 to the side of the ceiling plate
11 and the peripheral direction and a wall portion vertically
extending from the side of the ceiling plate 11 to the side of the
turntable 2 and the peripheral direction. These wall portions are
alternately arranged in a radius direction of the turntable 2.
[0064] Referring to FIGS. 2 to 4, the transfer opening 15 is formed
in the side wall of the vacuum chamber 1. The transfer opening 15
is provided to serve or receive the wafer W between a transfer arm
(not illustrated) and the turntable 2. The transfer opening 15 can
be hermetically opened or closed using a gate valve G. Further, a
lift pin (not illustrated) for lifting the wafer W from the back
surface side of the wafer through a through hole formed in the
turntable 2 is provided on the lower side of the turntable 2 at a
position corresponding to the transfer opening 15.
[0065] The film forming deposition apparatus includes a control
unit 120 having a computer for controlling entire operations of the
plasma processing apparatus as illustrated in FIG. 1. A program for
performing a film deposition process described below is stored in a
memory of the control part 120. The program is made to perform
steps of the following operations of the plasma processing
apparatus. The program is installed in the control unit 120 from a
memory unit 121 being a recording medium such as a hard disk, a
compact disk, a magneto-optical disk, a memory card, and a flexible
disk.
[0066] Next, functions of the above embodiment are described. At
first, the gate valve G is released. While the turntable 2 is
intermittently rotated, for example, five wafers W are mounted onto
the turntable 2 by the transfer arm (not illustrated) through the
transfer opening 15. Subsequently, the gate valve G is closed. The
inside of the vacuum chamber 1 is completely evacuated by the
vacuum pump 64, and simultaneously the turntable 2 is rotated at,
for example, 2 rpm to 240 rpm in the clockwise direction. Then, the
wafer W is heated to, for example, about 300.degree. C. by the
heater unit 7.
[0067] Subsequently, a DCS gas is discharged from the process gas
nozzle 31, and simultaneously an ammonia gas is discharged from the
plasma generating gas nozzle 32 so that the pressure in the
reaction area P2 has a positive pressure than areas inside the
vacuum chamber 1 other than the reaction area P2 inside the vacuum
chamber 1. Further, a separation gas is discharged from the
separation gas nozzles 41 and 42, and a nitrogen gas is discharged
from the separation gas supplying tube 51 and purge gas supplying
pipes 72 and 73. The inside of the vacuum chamber 1 is adjusted to
have a predetermined processing pressure by the pressure controller
65. Further, high frequency power is supplied to the antenna
83.
[0068] In the adsorption area P1, a component of the DCS gas
adsorbs onto the surface of the wafer W thereby producing an
adsorption layer. When the wafer W passes through the adsorption
area P1, a movement speed is faster on the side of the outer
periphery of the turntable 2 than on the side of the center of the
turntable 2 when the wafer W passes through the adsorption area P1.
Therefore, the film thickness on the side of the outer periphery of
the turntable 2 is apt to become thinner than the film thickness on
the side of the center of the turntable 2. However, because the
component of the DCS gas is quickly adsorbed, the adsorption layer
is uniformly formed through the surface of the wafer when the wafer
W passes through the adsorption area P1.
[0069] Because the position of the second evacuation port 62 is set
in the reaction area P2, the ammonia gas discharged from the plasma
generating gas nozzle 32 collides against the wall portion 92 on
the upstream side in the rotational direction of the turntable 2,
and thereafter linearly flows toward the second evacuation port 62
as illustrated in FIG. 9. While the ammonia gas flows toward the
second evacuation port 62, the ammonia gas is quickly changed by
the magnetic field to the plasma on the side lower than the three
stages of the linear portions 83a of the antenna 83 as illustrated
in FIG. 10. Because the opening widths of the slits 97 are
identical in the radius direction of the turntable 2, the amounts
(the densities) of the generated plasma corresponding to the slits
97 are identical along the radius direction. Thus, the plasma flows
toward the second evacuation port 62.
[0070] When the ammonia radical is inactivated by the collision
against the wafer W or the like and changed back to the ammonia
gas, the ammonia radical is changed to the plasma again by the
magnetic field generated by the opposite portion 83b which is
arranged on the side of the second evacuation port 62 relative to
the linear portion 83a. Referring to FIG. 11, because the pressure
inside the reaction area P2 is set higher than the pressure inside
the areas inside the vacuum chamber 1 other than the reaction area
P2, the plasma of the ammonia gas fills the reaction area P2.
[0071] Further, since the dimension of the reaction area P2 is set
as described above, times while the plasma is supplied to the wafer
W on the turntable 2 become identical along the radius direction of
the turntable 2. When the wafer W passes through the reaction area
P2, the adsorption layer on the wafer W is uniformly nitrided
through the surface of the wafer W and a reaction layer (a silicon
nitride film) is formed. As described, as the wafers W alternately
pass through the adsorption area P1 and the reaction area P2 by the
rotation of the turntable, the multiple reaction layers are
laminated to thereby form the thin film.
[0072] Since the gas flow path 101 is formed on the side ring 100
on the side of the outer periphery of the casing 90, the gases are
evacuated through the gas flow path 101 and prevents from passing
through the casing 90 while the above sequential processes are
performed. Further, since the wall portion 92 is provided at the
peripheral edge on the lower side of the casing 90, the nitrogen
gas is prevented from intruding inside the casing 90.
[0073] Further, since the nitrogen gas is supplied between the
adsorption area P1 and the reaction area P2, the process gas and
the plasma generating gas (the plasma) is evacuated without
mutually mixing. Further, because the purge gas is supplied on the
lower side of the turntable 2, the gas dispersing toward the lower
side of the turntable 2 is pushed back toward the first and second
evacuation ports 61 and 62 by the purge gas. Further, since the
separation gas is supplied to the center area C, mixture of the
process gas and the plasma generating gas or the plasma is
prevented inside the center area C.
[0074] Within the embodiment, the plasma generating gas nozzle 32
is linearly arranged between the side of the center of the
turntable 2 and the side of the outer edge of the turntable 3, and
the linear portions 83a of the antenna 83 are provided along the
direction of the length of the plasma generating gas nozzle 32. The
Faraday shield 95 formed with the slits 97 is arranged between the
antenna 83 and the plasma generating gas nozzle 32. The slits 97
are not formed on the side lower than the portions extending from
the both ends of the linear portions 83a and curving and are formed
only in the portion corresponding to the linear portions 83a. Since
the shapes of the slits 97 are identical, the amounts of the
magnetic fields respectively passing through the slits 97 are
identical. Therefore, a high uniformity is obtainable through the
surface of the wafer W in the plasma process.
[0075] Further, the wall portion 92 is formed at the peripheral
edges on the side of the lower surface of the casing 90 and through
the peripheral direction, and simultaneously the discharge amount
of the ammonia gas in the reaction area P2 surrounded by the wall
portion 92 is adjusted to be higher than the areas of the vacuum
chamber 1 other than the reaction area P2. Further, the plasma
generating gas nozzle 32 is arranged inside the reaction area P2 on
the upstream side of the rotational direction of the turntable 2,
and simultaneously the discharge ports 33 of the plasma generating
gas nozzle 32 are formed to face the wall portion 92 on the
upstream side of the rotational direction. Therefore, since it is
possible to prevent the nitrogen gas from intruding into the
reaction area P2, it is possible to maintain a contact area between
the wafer W and the plasma to be wide through the reaction area
P2.
[0076] Further, a layout of the reaction area P2 is adjusted so
that a speed difference caused between the rotational speed of the
turntable 2 on the inner peripheral side and the rotational speed
of the turntable 2 on the outer peripheral side is solved. As
described above, since the amount of the plasma is uniformized
through the radius direction of the turntable 2 and a contact time
while the plasma contacts the wafer W is uniformized, the uniform
plasma process can be performed through the surface of the wafer W.
Said differently, since the DCS gas quickly adsorbs onto the wafer
W as described above, the adsorption layer is uniformly formed
through the surface of the wafer W. On the other hand, the plasma
of the ammonia gas does not have a high reactivity when the
adsorption layer is reacted. Therefore, by uniformizing the density
of the plasma and the contact time while the plasma contacts the
wafer, the film thickness of the reaction product can be
uniformized through the surface of the wafer W.
[0077] Further, the linear portions 83a are laminated in the
vertical direction, and the opposite portions 83b are arranged in
the horizontal direction. Therefore, the plasma of the ammonia gas
is quickly generated at the position lower than the linear portion
83a. Meanwhile, the ammonia gas generated when the plasma is
inactivated is again changed to the plasma on the side lower than
the opposite portion 83b. As described above, it is possible to
widely maintain the plasma in the reaction area P2. When the
ammonia gas is changed again to the plasma, the opposite portions
83b are arranged for the magnetic field component necessary for
changing to the plasma. However, the opposite portions 83b are not
excessively provided. Further, the linear portion 83a and the
opposite portion 83b are connected in common to the high frequency
power source 85. It is possible to perform a process with the high
uniformity while restricting the cost of the plasma processing
apparatus from increasing.
[0078] Further, since the slits 97 are not formed on the upper side
of the plasma generating gas nozzle 32, it is possible to restrict
an extraneous matter such as the reaction product from attaching to
the inside or the outer wall of the plasma generating gas nozzle
32.
[0079] FIG. 12 illustrates another embodiment of the present
invention. Said differently, the opposite portions 83b may be
laminated in the vertical direction. Alternatively, an auxiliary
antenna 300 that changes the ammonia gas generated when the plasma
is inactivated again to the plasma may be provided on the
downstream side in the rotational direction of the turntable 2
relative to the antenna 83 in addition to the antenna including the
linear portions 83a and the opposite portions 83b. The auxiliary
antenna 300 may be connected to the high frequency power source 85
for the antenna 83 or another high frequency power source different
from the high frequency power source 85.
[0080] FIG. 13 illustrates a result of a simulation of a
distribution of the ammonia gas on the lower side of the casing 90.
Referring to FIG. 13, the ammonia gas supplied from the plasma
generating gas nozzle 32 to the reaction area P2 flows toward the
second evacuation port 62 while diffusing inside the reaction area
P2. Therefore, the ammonia gas (the plasma) can be diffused through
the reaction area P2 by arranging the second evacuation port 62 on
the downstream side in the rotational direction of the turntable 2
relative to the casing 90 and outside the turntable 2.
[0081] Although not only the linear portions 83a but also the
opposite portions 83b are linearly arranged in FIG. 6 illustrated
above, the opposite portions 83b may be arranged in a curved shape
so that the antenna 83 is shaped in a semicircle in its plan view.
The slits 97 may be arranged along the length direction of the
opposite portions 83b. Said differently, within the embodiment of
the present invention, it is sufficient to linearly arrange the
antenna 83 at a portion corresponding to the area where the wafer W
passes and in the vicinity of the plasma generating gas nozzle3 32.
Therefore, the other portions (the opposite portions 83b and the
curved portions 83c) of the antenna 83 may be shaped like a curved
line. Further, the slits 97 may be formed for the curved portions
83c in the vicinity of the opposite portion 83b. Within the
embodiment of the present invention, "the curved portion 83a
without the slit 97" is defined as a portion of the antenna 83
extending from the ends of the linear portion and area and curved.
Within the previous embodiment, the curved portions 83c are wound
by three times in the vertical direction. Instead of winding the
antenna 83 around the vertical axis to form the three stages, the
antenna 83 may be formed by winging by only one stage.
[0082] Further, instead of the plasma generating gas nozzle 32 of a
gas injector type, a substantially box-like body having an opening
on its lower surface side and extending along the radius direction
of the turntable 2 may be provided inside the vacuum chamber 1 and
the gas discharge ports 33 may be formed in the length direction of
the substantially box-like body.
[0083] The type of the film deposited using the plasma processing
apparatus described above is a silicon oxide (SiO.sub.2) film, a
titanium nitride (TiN) film, or the like instead of the silicon
nitride film. In a case where the silicon oxide film is deposited,
the plasma generating gas is, for example, oxygen (O.sub.2) gas. In
a case where the titanium nitride film is deposited, the adsorption
gas and the plasma generating gas are an organic gas containing
titanium and ammonia gas containing titanium, respectively. The
present invention is applicable to the film deposition of the
reaction product made of a nitride, an oxide, or a hydride in
addition to the silicon nitride film and the titanium nitride film.
The plasma generating gases used to deposit films of the nitride,
the oxide, or the hydride are ammonia gas, oxygen gas, and hydrogen
(H.sub.2) gas, respectively.
[0084] The plasma generating gas nozzle 32 and the casing 90
described above may be arranged at a position on the downstream
side in the rotational direction of the turntable 2 relative to the
adsorption area P1 and on the upstream side in the rotational
direction of the turntable 2 relative to the reaction area P2 and
another plasma process may be performed at the position. In the
other plasma process, an argon (Ar) gas is used as the plasma
generating gas to perform a plasma altering process for the
reaction product produced on the wafer W. The plasma altering
process may be performed every lamination of one layer of multiple
layers of the reaction product. Said differently, the plasma
altering process may be performed every rotation of multiple
rotations of the turntable 2.
[0085] Within the embodiment of the present invention, nozzle
portions for supplying the plasma generating gas into the vacuum
chamber are linearly arranged, and the linear portions of the
antenna for generating the electromagnetic field (the electric
field and the magnetic field) are formed along the length
directions of the nozzle portions. Further, the Faraday shield is
arranged between the antenna and the nozzle portions, the slits are
formed in the Faraday shield at positions facing the linear
portion, and the electric field of the electromagnetic field
generated by the antenna is cut off to cause the magnetic field to
pass therethrough. Meanwhile, the slits are not formed at positions
facing the portions curving from both ends of the linear portions
to cut off not only the electric field but also the magnetic field.
The shapes of the slits are set to be identical. Therefore, the
amounts of the magnetic field reaching the inside of the vacuum
chamber can be uniformized along the length directions of the
nozzle portions. Therefore, a high uniformity is obtainable in
processing the surface of the substrate.
[0086] All examples and conditional language recited herein are
intended for pedagogical purposes to aid the reader in
understanding the embodiments and the concepts contributed by the
inventor to furthering the art, and are to be construed as being
without limitation to such specifically recited examples and
conditions, nor does the organization of such examples in the
specification relate to a showing of superiority or inferiority of
the embodiments. Although the plasma processing apparatus has been
described in detail, it should be understood that the various
changes, substitutions, and alterations could be made hereto
without departing from the spirit and scope of the invention.
* * * * *